Implantable sensors provide real time readings for one or more physiological parameters in a patient. Sensors may be used for monitoring a variety of bodily properties, such as temperature, pressure, fluid flow, or biochemical properties. Implantable sensors, suitable for use within the body, are capable of remote data transmission and, in recent years, have become compact in size and long lasting.
Implantable sensors may be secured within a lumen or other bodily cavity using a variety of devices, for example, an anchor. Where an expandable anchor is used, the anchor is compressed for delivery through the blood vessels and expanded at a target site to engage the vessel wall. The sensor must be secured to the anchor while the compressed anchor is delivered, and remain secured once the anchor is expanded at the target site. Further, the sensor must maintain its ability to measure and transmit data following delivery and expansion. Thus, accurate placement of the anchor and sensor is critical for the reliable measurement of a selected physiological parameter. Inaccurate positioning of a sensor jeopardizes the integrity of the sensor's readings. For example, if the sensor is not in sufficient contact with the blood due to cellular ingrowth around the sensor, accurate blood pressure readings cannot be obtained.
In order to minimize endothelial cell growth around the sensor, it is desirable to position the sensor a distance from the vessel wall when the anchor is implanted. Positioning the sensor away from the vessel wall also reduces interference from the vessel tissue and reduces any cellular or plaque buildup on the sensor. However, because the anchor is generally pressed against the vessel wall to maintain its position in the vessel and the sensor is attached to the anchor, current anchoring systems do not generally permit a sensor to be displaced from the anchor. Therefore, there is a need for an anchor sensor device with a sensor capable of being compressed to maintain deliverability, yet maximize the accuracy of the sensor at the target site once the anchor is implanted.